An embodiment of the invention relates to displaying three-dimensional (3D) images of an object that may be acquired in radiology, and in particular to representing anatomical sites in preparation for, or even during, a therapeutic act performed by interventional radiology or by surgery.
More particularly, an embodiment of the invention relates to tools enabling an optimum orientation to be identified for a biological object represented in three dimensions or enabling an optimum selection to be made for presenting a section of such an object on a display, such as a screen.
In the field of interventional radiology, therapeutic tools are presently deployed and moved under fluoroscopic guidance. To do this, it is desired visually to find an appropriate working view by orienting the imaging system, where such orientation provides a suitable display of the pathology to be treated. With complex pathologies such as cerebral aneurysms, it is difficult for a radiologist or other practitioner to find such a suitable working view.
Prior to the introduction of three-dimensional tools in angiography theaters, it was typically the practice to take a series of recordings or acquisitions under different angles selected empirically until a satisfactory view was obtained. That approach had several drawbacks, and in particular the high dose of radiation, such as X-rays, administered to the patient and also the high dose of injected contrast media. Furthermore, the time devoted to that procedure could be lengthy.
With the introduction of tools with three-dimensional representation, the preferred technique for selecting the working view has been transformed considerably. In a first step, 3D acquisition is performed, and then the radiologist examines the image displayed on a computer screen in three dimensions while interactively applying rotations to the 3D model until an acceptable view is found. In a second step, the user transmits the selected angle of observation to a radiological acquisition system as a control parameter for automatically moving the gantry until the desired working view is obtained.
Interactive rotation of the image in three dimensions has the advantage of not requiring repeated doses of X-rays and of not requiring repeated doses of contrast medium. Nevertheless, the quality of the result depends essentially on the skill of the user in interactively rotating the three-dimensional image. In addition, that technique does not save a significant amount of time compared with the earlier techniques. Furthermore, that technique does not ensure that the selected working view is the optimum view, given that the selection is based essentially on the skill of the user in manipulating a 3D image. In other words, there might be some other direction of observation that is better than that found by the user, but which the user did not find.